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<h2><span class="refentrytitle"><a name="GstBaseSrc.top_of_page"></a>GstBaseSrc</span></h2>
<p>GstBaseSrc — Base class for getrange based source elements</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
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<div class="refsect1">
<a name="GstBaseSrc.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<a href="../html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-wait-playing" title="gst_base_src_wait_playing ()">gst_base_src_wait_playing</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-start-wait" title="gst_base_src_start_wait ()">gst_base_src_start_wait</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-start-complete" title="gst_base_src_start_complete ()">gst_base_src_start_complete</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-is-live" title="gst_base_src_is_live ()">gst_base_src_is_live</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-live" title="gst_base_src_set_live ()">gst_base_src_set_live</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()">gst_base_src_set_format</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-query-latency" title="gst_base_src_query_latency ()">gst_base_src_query_latency</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-get-blocksize" title="gst_base_src_get_blocksize ()">gst_base_src_get_blocksize</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-blocksize" title="gst_base_src_set_blocksize ()">gst_base_src_set_blocksize</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-get-do-timestamp" title="gst_base_src_get_do_timestamp ()">gst_base_src_get_do_timestamp</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-do-timestamp" title="gst_base_src_set_do_timestamp ()">gst_base_src_set_do_timestamp</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-dynamic-size" title="gst_base_src_set_dynamic_size ()">gst_base_src_set_dynamic_size</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-automatic-eos" title="gst_base_src_set_automatic_eos ()">gst_base_src_set_automatic_eos</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-new-seamless-segment" title="gst_base_src_new_seamless_segment ()">gst_base_src_new_seamless_segment</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-caps" title="gst_base_src_set_caps ()">gst_base_src_set_caps</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-get-allocator" title="gst_base_src_get_allocator ()">gst_base_src_get_allocator</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="../html/GstBufferPool.html#GstBufferPool-struct"><span class="returnvalue">GstBufferPool</span></a> *
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-get-buffer-pool" title="gst_base_src_get_buffer_pool ()">gst_base_src_get_buffer_pool</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-is-async" title="gst_base_src_is_async ()">gst_base_src_is_async</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-set-async" title="gst_base_src_set_async ()">gst_base_src_set_async</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#gst-base-src-submit-buffer-list" title="gst_base_src_submit_buffer_list ()">gst_base_src_submit_buffer_list</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#GST-BASE-SRC-PAD:CAPS" title="GST_BASE_SRC_PAD()">GST_BASE_SRC_PAD</a><span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#GST-BASE-SRC-IS-STARTED:CAPS" title="GST_BASE_SRC_IS_STARTED()">GST_BASE_SRC_IS_STARTED</a><span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name">
<a class="link" href="GstBaseSrc.html#GST-BASE-SRC-IS-STARTING:CAPS" title="GST_BASE_SRC_IS_STARTING()">GST_BASE_SRC_IS_STARTING</a><span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.properties"></a><h2>Properties</h2>
<div class="informaltable"><table class="informaltable" border="0">
<colgroup>
<col width="150px" class="properties_type">
<col width="300px" class="properties_name">
<col width="200px" class="properties_flags">
</colgroup>
<tbody>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a></td>
<td class="property_name"><a class="link" href="GstBaseSrc.html#GstBaseSrc--blocksize" title="The “blocksize” property">blocksize</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="GstBaseSrc.html#GstBaseSrc--do-timestamp" title="The “do-timestamp” property">do-timestamp</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a></td>
<td class="property_name"><a class="link" href="GstBaseSrc.html#GstBaseSrc--num-buffers" title="The “num-buffers” property">num-buffers</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="GstBaseSrc.html#GstBaseSrc--typefind" title="The “typefind” property">typefind</a></td>
<td class="property_flags">Read / Write</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody>
<tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="GstBaseSrc.html#GstBaseSrc-struct" title="struct GstBaseSrc">GstBaseSrc</a></td>
</tr>
<tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="GstBaseSrc.html#GstBaseSrcClass" title="struct GstBaseSrcClass">GstBaseSrcClass</a></td>
</tr>
<tr>
<td class="datatype_keyword">enum</td>
<td class="function_name"><a class="link" href="GstBaseSrc.html#GstBaseSrcFlags" title="enum GstBaseSrcFlags">GstBaseSrcFlags</a></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="screen">    <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject-struct">GObject</a>
    <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
        <span class="lineart">╰──</span> <a href="../html/GstObject.html#GstObject-struct">GstObject</a>
            <span class="lineart">╰──</span> <a href="../html/GstElement.html#GstElement-struct">GstElement</a>
                <span class="lineart">╰──</span> GstBaseSrc
                    <span class="lineart">╰──</span> <a class="link" href="GstPushSrc.html" title="GstPushSrc">GstPushSrc</a>
</pre>
</div>
<div class="refsect1">
<a name="GstBaseSrc.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include &lt;gst/base/base.h&gt;
</pre>
</div>
<div class="refsect1">
<a name="GstBaseSrc.description"></a><h2>Description</h2>
<p>This is a generic base class for source elements. The following
types of sources are supported:</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>random access sources like files</p></li>
<li class="listitem"><p>seekable sources</p></li>
<li class="listitem"><p>live sources</p></li>
</ul></div>
<p>The source can be configured to operate in any <a href="../html/gstreamer-GstFormat.html#GstFormat"><span class="type">GstFormat</span></a> with the
<a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></a> method. The currently set format determines
the format of the internal <a href="../html/GstSegment.html#GstSegment-struct"><span class="type">GstSegment</span></a> and any <a href="../html/GstEvent.html#GST-EVENT-SEGMENT:CAPS"><code class="literal">GST_EVENT_SEGMENT</code></a>
events. The default format for <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> is <a href="../html/gstreamer-GstFormat.html#GST-FORMAT-BYTES:CAPS"><code class="literal">GST_FORMAT_BYTES</code></a>.</p>
<p><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> always supports push mode scheduling. If the following
conditions are met, it also supports pull mode scheduling:</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>The format is set to <a href="../html/gstreamer-GstFormat.html#GST-FORMAT-BYTES:CAPS"><code class="literal">GST_FORMAT_BYTES</code></a> (default).</p></li>
<li class="listitem"><p><a class="link" href="GstBaseSrc.html#GstBaseSrcClass.is-seekable"><code class="function">GstBaseSrcClass.is_seekable()</code></a> returns <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.</p></li>
</ul></div>
<p>If all the conditions are met for operating in pull mode, <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> is
automatically seekable in push mode as well. The following conditions must
be met to make the element seekable in push mode when the format is not
<a href="../html/gstreamer-GstFormat.html#GST-FORMAT-BYTES:CAPS"><code class="literal">GST_FORMAT_BYTES</code></a>:</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p><a class="link" href="GstBaseSrc.html#GstBaseSrcClass.is-seekable"><code class="function">GstBaseSrcClass.is_seekable()</code></a> returns <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.</p></li>
<li class="listitem"><p><a class="link" href="GstBaseSrc.html#GstBaseSrcClass.query"><code class="function">GstBaseSrcClass.query()</code></a> can convert all supported seek formats to the
internal format as set with <a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></a>.</p></li>
<li class="listitem"><p><a class="link" href="GstBaseSrc.html#GstBaseSrcClass.do-seek"><code class="function">GstBaseSrcClass.do_seek()</code></a> is implemented, performs the seek and returns
<a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.</p></li>
</ul></div>
<p>When the element does not meet the requirements to operate in pull mode, the
offset and length in the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> method should be ignored.
It is recommended to subclass <a class="link" href="GstPushSrc.html" title="GstPushSrc"><span class="type">GstPushSrc</span></a> instead, in this situation. If the
element can operate in pull mode but only with specific offsets and
lengths, it is allowed to generate an error when the wrong values are passed
to the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> function.</p>
<p><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> has support for live sources. Live sources are sources that when
paused discard data, such as audio or video capture devices. A typical live
source also produces data at a fixed rate and thus provides a clock to publish
this rate.
Use <a class="link" href="GstBaseSrc.html#gst-base-src-set-live" title="gst_base_src_set_live ()"><code class="function">gst_base_src_set_live()</code></a> to activate the live source mode.</p>
<p>A live source does not produce data in the PAUSED state. This means that the
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> method will not be called in PAUSED but only in
PLAYING. To signal the pipeline that the element will not produce data, the
return value from the READY to PAUSED state will be
<a href="../html/GstElement.html#GST-STATE-CHANGE-NO-PREROLL:CAPS"><code class="literal">GST_STATE_CHANGE_NO_PREROLL</code></a>.</p>
<p>A typical live source will timestamp the buffers it creates with the
current running time of the pipeline. This is one reason why a live source
can only produce data in the PLAYING state, when the clock is actually
distributed and running.</p>
<p>Live sources that synchronize and block on the clock (an audio source, for
example) can use <a class="link" href="GstBaseSrc.html#gst-base-src-wait-playing" title="gst_base_src_wait_playing ()"><code class="function">gst_base_src_wait_playing()</code></a> when the
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> function was interrupted by a state change to
PAUSED.</p>
<p>The <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.get-times"><code class="function">GstBaseSrcClass.get_times()</code></a> method can be used to implement pseudo-live
sources. It only makes sense to implement the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.get-times"><code class="function">GstBaseSrcClass.get_times()</code></a>
function if the source is a live source. The <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.get-times"><code class="function">GstBaseSrcClass.get_times()</code></a>
function should return timestamps starting from 0, as if it were a non-live
source. The base class will make sure that the timestamps are transformed
into the current running_time. The base source will then wait for the
calculated running_time before pushing out the buffer.</p>
<p>For live sources, the base class will by default report a latency of 0.
For pseudo live sources, the base class will by default measure the difference
between the first buffer timestamp and the start time of get_times and will
report this value as the latency.
Subclasses should override the query function when this behaviour is not
acceptable.</p>
<p>There is only support in <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> for exactly one source pad, which
should be named "src". A source implementation (subclass of <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>)
should install a pad template in its class_init function, like so:</p>
<div class="informalexample">
  <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
    <tbody>
      <tr>
        <td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14</pre></td>
        <td class="listing_code"><pre class="programlisting"><span class="gtkdoc kwb">static void</span>
<span class="function">my_element_class_init</span> <span class="gtkdoc opt">(</span>GstMyElementClass <span class="gtkdoc opt">*</span>klass<span class="gtkdoc opt">)</span>
<span class="gtkdoc opt">{</span>
  GstElementClass <span class="gtkdoc opt">*</span>gstelement_class <span class="gtkdoc opt">=</span> <span class="function">GST_ELEMENT_CLASS</span> <span class="gtkdoc opt">(</span>klass<span class="gtkdoc opt">);</span>
  <span class="gtkdoc slc">// srctemplate should be a #GstStaticPadTemplate with direction</span>
  <span class="gtkdoc slc">// %GST_PAD_SRC and name &quot;src&quot;</span>
  <span class="function"><a href="../html/GstElement.html#gst-element-class-add-static-pad-template">gst_element_class_add_static_pad_template</a></span> <span class="gtkdoc opt">(</span>gstelement_class<span class="gtkdoc opt">, &amp;</span>srctemplate<span class="gtkdoc opt">);</span>

  <span class="function"><a href="../html/GstElement.html#gst-element-class-set-static-metadata">gst_element_class_set_static_metadata</a></span> <span class="gtkdoc opt">(</span>gstelement_class<span class="gtkdoc opt">,</span>
     <span class="string">&quot;Source name&quot;</span><span class="gtkdoc opt">,</span>
     <span class="string">&quot;Source&quot;</span><span class="gtkdoc opt">,</span>
     <span class="string">&quot;My Source element&quot;</span><span class="gtkdoc opt">,</span>
     <span class="string">&quot;The author &lt;my.sink&#64;my.email&gt;&quot;</span><span class="gtkdoc opt">);</span>
<span class="gtkdoc opt">}</span></pre></td>
      </tr>
    </tbody>
  </table>
</div>

<p></p>
<div class="refsect3">
<a name="id-1.2.4.6.8.19"></a><h4>Controlled shutdown of live sources in applications</h4>
<p>Applications that record from a live source may want to stop recording
in a controlled way, so that the recording is stopped, but the data
already in the pipeline is processed to the end (remember that many live
sources would go on recording forever otherwise). For that to happen the
application needs to make the source stop recording and send an EOS
event down the pipeline. The application would then wait for an
EOS message posted on the pipeline's bus to know when all data has
been processed and the pipeline can safely be stopped.</p>
<p>An application may send an EOS event to a source element to make it
perform the EOS logic (send EOS event downstream or post a
<a href="../html/GstMessage.html#GST-MESSAGE-SEGMENT-DONE:CAPS"><code class="literal">GST_MESSAGE_SEGMENT_DONE</code></a> on the bus). This can typically be done
with the <a href="../html/GstElement.html#gst-element-send-event"><code class="function">gst_element_send_event()</code></a> function on the element or its parent bin.</p>
<p>After the EOS has been sent to the element, the application should wait for
an EOS message to be posted on the pipeline's bus. Once this EOS message is
received, it may safely shut down the entire pipeline.</p>
</div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="gst-base-src-wait-playing"></a><h3>gst_base_src_wait_playing ()</h3>
<pre class="programlisting"><a href="../html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a>
gst_base_src_wait_playing (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>If the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> method performs its own synchronisation
against the clock it must unblock when going from PLAYING to the PAUSED state
and call this method before continuing to produce the remaining data.</p>
<p>This function will block until a state change to PLAYING happens (in which
case this function returns <a href="../html/GstPad.html#GST-FLOW-OK:CAPS"><code class="literal">GST_FLOW_OK</code></a>) or the processing must be stopped due
to a state change to READY or a FLUSH event (in which case this function
returns <a href="../html/GstPad.html#GST-FLOW-FLUSHING:CAPS"><code class="literal">GST_FLOW_FLUSHING</code></a>).</p>
<div class="refsect3">
<a name="gst-base-src-wait-playing.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>the src</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-wait-playing.returns"></a><h4>Returns</h4>
<p> <a href="../html/GstPad.html#GST-FLOW-OK:CAPS"><code class="literal">GST_FLOW_OK</code></a> if <em class="parameter"><code>src</code></em>
is PLAYING and processing can
continue. Any other return value should be returned from the create vmethod.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-start-wait"></a><h3>gst_base_src_start_wait ()</h3>
<pre class="programlisting"><a href="../html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a>
gst_base_src_start_wait (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *basesrc</code></em>);</pre>
<p>Wait until the start operation completes.</p>
<div class="refsect3">
<a name="gst-base-src-start-wait.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>basesrc</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-start-wait.returns"></a><h4>Returns</h4>
<p> a <a href="../html/GstPad.html#GstFlowReturn"><span class="type">GstFlowReturn</span></a>.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-start-complete"></a><h3>gst_base_src_start_complete ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_start_complete (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *basesrc</code></em>,
                             <em class="parameter"><code><a href="../html/GstPad.html#GstFlowReturn"><span class="type">GstFlowReturn</span></a> ret</code></em>);</pre>
<p>Complete an asynchronous start operation. When the subclass overrides the
start method, it should call <a class="link" href="GstBaseSrc.html#gst-base-src-start-complete" title="gst_base_src_start_complete ()"><code class="function">gst_base_src_start_complete()</code></a> when the start
operation completes either from the same thread or from an asynchronous
helper thread.</p>
<div class="refsect3">
<a name="gst-base-src-start-complete.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>basesrc</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>ret</p></td>
<td class="parameter_description"><p>a <a href="../html/GstPad.html#GstFlowReturn"><span class="type">GstFlowReturn</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-is-live"></a><h3>gst_base_src_is_live ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_base_src_is_live (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>Check if an element is in live mode.</p>
<div class="refsect3">
<a name="gst-base-src-is-live.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-is-live.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if element is in live mode.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-live"></a><h3>gst_base_src_set_live ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_live (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                       <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> live</code></em>);</pre>
<p>If the element listens to a live source, <em class="parameter"><code>live</code></em>
 should
be set to <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.</p>
<p>A live source will not produce data in the PAUSED state and
will therefore not be able to participate in the PREROLL phase
of a pipeline. To signal this fact to the application and the
pipeline, the state change return value of the live source will
be GST_STATE_CHANGE_NO_PREROLL.</p>
<div class="refsect3">
<a name="gst-base-src-set-live.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>live</p></td>
<td class="parameter_description"><p>new live-mode</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-format"></a><h3>gst_base_src_set_format ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_format (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                         <em class="parameter"><code><a href="../html/gstreamer-GstFormat.html#GstFormat"><span class="type">GstFormat</span></a> format</code></em>);</pre>
<p>Sets the default format of the source. This will be the format used
for sending SEGMENT events and for performing seeks.</p>
<p>If a format of GST_FORMAT_BYTES is set, the element will be able to
operate in pull mode if the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.is-seekable"><code class="function">GstBaseSrcClass.is_seekable()</code></a> returns <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.</p>
<p>This function must only be called in states &lt; <a href="../html/GstElement.html#GST-STATE-PAUSED:CAPS"><code class="literal">GST_STATE_PAUSED</code></a>.</p>
<div class="refsect3">
<a name="gst-base-src-set-format.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>format</p></td>
<td class="parameter_description"><p>the format to use</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-query-latency"></a><h3>gst_base_src_query_latency ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_base_src_query_latency (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                            <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> *live</code></em>,
                            <em class="parameter"><code><a href="../html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> *min_latency</code></em>,
                            <em class="parameter"><code><a href="../html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> *max_latency</code></em>);</pre>
<p>Query the source for the latency parameters. <em class="parameter"><code>live</code></em>
 will be <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> when <em class="parameter"><code>src</code></em>
 is
configured as a live source. <em class="parameter"><code>min_latency</code></em>
 and <em class="parameter"><code>max_latency</code></em>
 will be set
to the difference between the running time and the timestamp of the first
buffer.</p>
<p>This function is mostly used by subclasses.</p>
<div class="refsect3">
<a name="gst-base-src-query-latency.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>the source</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>live</p></td>
<td class="parameter_description"><p>if the source is live. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>min_latency</p></td>
<td class="parameter_description"><p>the min latency of the source. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>max_latency</p></td>
<td class="parameter_description"><p>the max latency of the source. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-query-latency.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the query succeeded.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-blocksize"></a><h3>gst_base_src_get_blocksize ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a>
gst_base_src_get_blocksize (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>Get the number of bytes that <em class="parameter"><code>src</code></em>
 will push out with each buffer.</p>
<div class="refsect3">
<a name="gst-base-src-get-blocksize.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>the source</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-get-blocksize.returns"></a><h4>Returns</h4>
<p> the number of bytes pushed with each buffer.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-blocksize"></a><h3>gst_base_src_set_blocksize ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_blocksize (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                            <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a> blocksize</code></em>);</pre>
<p>Set the number of bytes that <em class="parameter"><code>src</code></em>
 will push out with each buffer. When
<em class="parameter"><code>blocksize</code></em>
 is set to -1, a default length will be used.</p>
<div class="refsect3">
<a name="gst-base-src-set-blocksize.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>the source</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>blocksize</p></td>
<td class="parameter_description"><p>the new blocksize in bytes</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-do-timestamp"></a><h3>gst_base_src_get_do_timestamp ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_base_src_get_do_timestamp (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>Query if <em class="parameter"><code>src</code></em>
 timestamps outgoing buffers based on the current running_time.</p>
<div class="refsect3">
<a name="gst-base-src-get-do-timestamp.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>the source</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-get-do-timestamp.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the base class will automatically timestamp outgoing buffers.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-do-timestamp"></a><h3>gst_base_src_set_do_timestamp ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_do_timestamp (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                               <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> timestamp</code></em>);</pre>
<p>Configure <em class="parameter"><code>src</code></em>
 to automatically timestamp outgoing buffers based on the
current running_time of the pipeline. This property is mostly useful for live
sources.</p>
<div class="refsect3">
<a name="gst-base-src-set-do-timestamp.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>the source</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>timestamp</p></td>
<td class="parameter_description"><p>enable or disable timestamping</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-dynamic-size"></a><h3>gst_base_src_set_dynamic_size ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_dynamic_size (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                               <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> dynamic</code></em>);</pre>
<p>If not <em class="parameter"><code>dynamic</code></em>
, size is only updated when needed, such as when trying to
read past current tracked size.  Otherwise, size is checked for upon each
read.</p>
<div class="refsect3">
<a name="gst-base-src-set-dynamic-size.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>dynamic</p></td>
<td class="parameter_description"><p>new dynamic size mode</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-automatic-eos"></a><h3>gst_base_src_set_automatic_eos ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_automatic_eos (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                                <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> automatic_eos</code></em>);</pre>
<p>If <em class="parameter"><code>automatic_eos</code></em>
 is <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>, <em class="parameter"><code>src</code></em>
 will automatically go EOS if a buffer
after the total size is returned. By default this is <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> but sources
that can't return an authoritative size and only know that they're EOS
when trying to read more should set this to <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a>.</p>
<p>When <em class="parameter"><code>src</code></em>
 operates in <a href="../html/gstreamer-GstFormat.html#GST-FORMAT-TIME:CAPS"><code class="literal">GST_FORMAT_TIME</code></a>, <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> will send an EOS
when a buffer outside of the currently configured segment is pushed if
<em class="parameter"><code>automatic_eos</code></em>
 is <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>. Since 1.16, if <em class="parameter"><code>automatic_eos</code></em>
 is <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> an
EOS will be pushed only when the <span class="type">GstBaseSrc.create</span> implementation
returns <a href="../html/GstPad.html#GST-FLOW-EOS:CAPS"><code class="literal">GST_FLOW_EOS</code></a>.</p>
<div class="refsect3">
<a name="gst-base-src-set-automatic-eos.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>automatic_eos</p></td>
<td class="parameter_description"><p>automatic eos</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: <a class="link" href="ix09.html#api-index-1.4">1.4</a></p>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-new-seamless-segment"></a><h3>gst_base_src_new_seamless_segment ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_base_src_new_seamless_segment (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                                   <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint64"><span class="type">gint64</span></a> start</code></em>,
                                   <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint64"><span class="type">gint64</span></a> stop</code></em>,
                                   <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint64"><span class="type">gint64</span></a> time</code></em>);</pre>
<p>Prepare a new seamless segment for emission downstream. This function must
only be called by derived sub-classes, and only from the <code class="function">create()</code> function,
as the stream-lock needs to be held.</p>
<p>The format for the new segment will be the current format of the source, as
configured with <a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></a></p>
<div class="refsect3">
<a name="gst-base-src-new-seamless-segment.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>The source</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>start</p></td>
<td class="parameter_description"><p>The new start value for the segment</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>stop</p></td>
<td class="parameter_description"><p>Stop value for the new segment</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>time</p></td>
<td class="parameter_description"><p>The new time value for the start of the new segment</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-new-seamless-segment.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if preparation of the seamless segment succeeded.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-caps"></a><h3>gst_base_src_set_caps ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_base_src_set_caps (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                       <em class="parameter"><code><a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a> *caps</code></em>);</pre>
<p>Set new caps on the basesrc source pad.</p>
<div class="refsect3">
<a name="gst-base-src-set-caps.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>caps</p></td>
<td class="parameter_description"><p>a <a href="../html/GstCaps.html#GstCaps-struct"><span class="type">GstCaps</span></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-set-caps.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the caps could be set</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-allocator"></a><h3>gst_base_src_get_allocator ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_get_allocator (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                            <em class="parameter"><code><a href="../html/GstAllocator.html#GstAllocator-struct"><span class="type">GstAllocator</span></a> **allocator</code></em>,
                            <em class="parameter"><code><a href="../html/GstAllocator.html#GstAllocationParams-struct"><span class="type">GstAllocationParams</span></a> *params</code></em>);</pre>
<p>Lets <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> sub-classes to know the memory <em class="parameter"><code>allocator</code></em>

used by the base class and its <em class="parameter"><code>params</code></em>
.</p>
<p>Unref the <em class="parameter"><code>allocator</code></em>
 after usage.</p>
<div class="refsect3">
<a name="gst-base-src-get-allocator.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>allocator</p></td>
<td class="parameter_description"><p>the <a href="../html/GstAllocator.html#GstAllocator-struct"><span class="type">GstAllocator</span></a>
used. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>][<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>params</p></td>
<td class="parameter_description"><p>the
<a href="../html/GstAllocator.html#GstAllocationParams-struct"><span class="type">GstAllocationParams</span></a> of <em class="parameter"><code>allocator</code></em>
. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>][<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-buffer-pool"></a><h3>gst_base_src_get_buffer_pool ()</h3>
<pre class="programlisting"><a href="../html/GstBufferPool.html#GstBufferPool-struct"><span class="returnvalue">GstBufferPool</span></a> *
gst_base_src_get_buffer_pool (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<div class="refsect3">
<a name="gst-base-src-get-buffer-pool.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-get-buffer-pool.returns"></a><h4>Returns</h4>
<p>the instance of the <a href="../html/GstBufferPool.html#GstBufferPool-struct"><span class="type">GstBufferPool</span></a> used
by the src; unref it after usage. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-is-async"></a><h3>gst_base_src_is_async ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_base_src_is_async (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>Get the current async behaviour of <em class="parameter"><code>src</code></em>
. See also <a class="link" href="GstBaseSrc.html#gst-base-src-set-async" title="gst_base_src_set_async ()"><code class="function">gst_base_src_set_async()</code></a>.</p>
<div class="refsect3">
<a name="gst-base-src-is-async.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-base-src-is-async.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <em class="parameter"><code>src</code></em>
is operating in async mode.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-async"></a><h3>gst_base_src_set_async ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_set_async (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                        <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> async</code></em>);</pre>
<p>Configure async behaviour in <em class="parameter"><code>src</code></em>
, no state change will block. The open,
close, start, stop, play and pause virtual methods will be executed in a
different thread and are thus allowed to perform blocking operations. Any
blocking operation should be unblocked with the unlock vmethod.</p>
<div class="refsect3">
<a name="gst-base-src-set-async.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>async</p></td>
<td class="parameter_description"><p>new async mode</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-submit-buffer-list"></a><h3>gst_base_src_submit_buffer_list ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_base_src_submit_buffer_list (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
                                 <em class="parameter"><code><a href="../html/GstBufferList.html#GstBufferList-struct"><span class="type">GstBufferList</span></a> *buffer_list</code></em>);</pre>
<p>Subclasses can call this from their create virtual method implementation
to submit a buffer list to be pushed out later. This is useful in
cases where the create function wants to produce multiple buffers to be
pushed out in one go in form of a <a href="../html/GstBufferList.html#GstBufferList-struct"><span class="type">GstBufferList</span></a>, which can reduce overhead
drastically, especially for packetised inputs (for data streams where
the packetisation/chunking is not important it is usually more efficient
to return larger buffers instead).</p>
<p>Subclasses that use this function from their create function must return
<a href="../html/GstPad.html#GST-FLOW-OK:CAPS"><code class="literal">GST_FLOW_OK</code></a> and no buffer from their create virtual method implementation.
If a buffer is returned after a buffer list has also been submitted via this
function the behaviour is undefined.</p>
<p>Subclasses must only call this function once per create function call and
subclasses must only call this function when the source operates in push
mode.</p>
<div class="refsect3">
<a name="gst-base-src-submit-buffer-list.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>src</p></td>
<td class="parameter_description"><p>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>buffer_list</p></td>
<td class="parameter_description"><p>a <a href="../html/GstBufferList.html#GstBufferList-struct"><span class="type">GstBufferList</span></a>. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: <a class="link" href="ix03.html#api-index-1.14">1.14</a></p>
</div>
<hr>
<div class="refsect2">
<a name="GST-BASE-SRC-PAD:CAPS"></a><h3>GST_BASE_SRC_PAD()</h3>
<pre class="programlisting">#define GST_BASE_SRC_PAD(obj)                 (GST_BASE_SRC_CAST (obj)-&gt;srcpad)
</pre>
<p>Gives the pointer to the <a href="../html/GstPad.html#GstPad-struct"><span class="type">GstPad</span></a> object of the element.</p>
<div class="refsect3">
<a name="GST-BASE-SRC-PAD.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>obj</p></td>
<td class="parameter_description"><p>base source instance</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="GST-BASE-SRC-IS-STARTED:CAPS"></a><h3>GST_BASE_SRC_IS_STARTED()</h3>
<pre class="programlisting">#define GST_BASE_SRC_IS_STARTED(obj)  GST_OBJECT_FLAG_IS_SET ((obj), GST_BASE_SRC_FLAG_STARTED)
</pre>
</div>
<hr>
<div class="refsect2">
<a name="GST-BASE-SRC-IS-STARTING:CAPS"></a><h3>GST_BASE_SRC_IS_STARTING()</h3>
<pre class="programlisting">#define GST_BASE_SRC_IS_STARTING(obj) GST_OBJECT_FLAG_IS_SET ((obj), GST_BASE_SRC_FLAG_STARTING)
</pre>
</div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstBaseSrc-struct"></a><h3>struct GstBaseSrc</h3>
<pre class="programlisting">struct GstBaseSrc;</pre>
<p>The opaque <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> data structure.</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrcClass"></a><h3>struct GstBaseSrcClass</h3>
<pre class="programlisting">struct GstBaseSrcClass {
  GstElementClass parent_class;

  /* virtual methods for subclasses */

  /* get caps from subclass */
  GstCaps*      (*get_caps)     (GstBaseSrc *src, GstCaps *filter);
  /* decide on caps */
  gboolean      (*negotiate)    (GstBaseSrc *src);
  /* called if, in negotiation, caps need fixating */
  GstCaps *     (*fixate)       (GstBaseSrc *src, GstCaps *caps);
  /* notify the subclass of new caps */
  gboolean      (*set_caps)     (GstBaseSrc *src, GstCaps *caps);

  /* setup allocation query */
  gboolean      (*decide_allocation)   (GstBaseSrc *src, GstQuery *query);

  /* start and stop processing, ideal for opening/closing the resource */
  gboolean      (*start)        (GstBaseSrc *src);
  gboolean      (*stop)         (GstBaseSrc *src);

  /**
   * GstBaseSrcClass::get_times:
   * @start: (out):
   * @end: (out):
   *
   * Given @buffer, return @start and @end time when it should be pushed
   * out. The base class will sync on the clock using these times.
   */
  void          (*get_times)    (GstBaseSrc *src, GstBuffer *buffer,
                                 GstClockTime *start, GstClockTime *end);

  /* get the total size of the resource in the format set by
   * gst_base_src_set_format() */
  gboolean      (*get_size)     (GstBaseSrc *src, guint64 *size);

  /* check if the resource is seekable */
  gboolean      (*is_seekable)  (GstBaseSrc *src);

  /* Prepare the segment on which to perform do_seek(), converting to the
   * current basesrc format. */
  gboolean      (*prepare_seek_segment) (GstBaseSrc *src, GstEvent *seek,
                                         GstSegment *segment);
  /* notify subclasses of a seek */
  gboolean      (*do_seek)      (GstBaseSrc *src, GstSegment *segment);

  /* unlock any pending access to the resource. subclasses should unlock
   * any function ASAP. */
  gboolean      (*unlock)       (GstBaseSrc *src);
  /* Clear any pending unlock request, as we succeeded in unlocking */
  gboolean      (*unlock_stop)  (GstBaseSrc *src);

  /* notify subclasses of a query */
  gboolean      (*query)        (GstBaseSrc *src, GstQuery *query);

  /* notify subclasses of an event */
  gboolean      (*event)        (GstBaseSrc *src, GstEvent *event);

  /**
   * GstBaseSrcClass::create:
   * @buf: (out):
   *
   * Ask the subclass to create a buffer with @offset and @size, the default
   * implementation will call alloc and fill.
   */
  GstFlowReturn (*create)       (GstBaseSrc *src, guint64 offset, guint size,
                                 GstBuffer **buf);
  /* ask the subclass to allocate an output buffer. The default implementation
   * will use the negotiated allocator. */
  GstFlowReturn (*alloc)        (GstBaseSrc *src, guint64 offset, guint size,
                                 GstBuffer **buf);
  /* ask the subclass to fill the buffer with data from offset and size */
  GstFlowReturn (*fill)         (GstBaseSrc *src, guint64 offset, guint size,
                                 GstBuffer *buf);
};
</pre>
<p>Subclasses can override any of the available virtual methods or not, as
needed. At the minimum, the <em class="parameter"><code>create</code></em>
 method should be overridden to produce
buffers.</p>
<div class="refsect3">
<a name="GstBaseSrcClass.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.get-caps"></a>get_caps</code></em> ()</p></td>
<td class="struct_member_description"><p>Called to get the caps to report</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.negotiate"></a>negotiate</code></em> ()</p></td>
<td class="struct_member_description"><p>Negotiated the caps with the peer.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.fixate"></a>fixate</code></em> ()</p></td>
<td class="struct_member_description"><p>Called during negotiation if caps need fixating. Implement instead of
setting a fixate function on the source pad.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.set-caps"></a>set_caps</code></em> ()</p></td>
<td class="struct_member_description"><p>Notify subclass of changed output caps</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.decide-allocation"></a>decide_allocation</code></em> ()</p></td>
<td class="struct_member_description"><p>configure the allocation query</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.start"></a>start</code></em> ()</p></td>
<td class="struct_member_description"><p>Start processing. Subclasses should open resources and prepare
to produce data. Implementation should call <a class="link" href="GstBaseSrc.html#gst-base-src-start-complete" title="gst_base_src_start_complete ()"><code class="function">gst_base_src_start_complete()</code></a>
when the operation completes, either from the current thread or any other
thread that finishes the start operation asynchronously.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.stop"></a>stop</code></em> ()</p></td>
<td class="struct_member_description"><p>Stop processing. Subclasses should use this to close resources.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.get-times"></a>get_times</code></em> ()</p></td>
<td class="struct_member_description"><p>Given a buffer, return the start and stop time when it
should be pushed out. The base class will sync on the clock using
these times.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.get-size"></a>get_size</code></em> ()</p></td>
<td class="struct_member_description"><p>Return the total size of the resource, in the format set by
<a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></a>.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.is-seekable"></a>is_seekable</code></em> ()</p></td>
<td class="struct_member_description"><p>Check if the source can seek</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.prepare-seek-segment"></a>prepare_seek_segment</code></em> ()</p></td>
<td class="struct_member_description"><p>Prepare the <a href="../html/GstSegment.html#GstSegment-struct"><span class="type">GstSegment</span></a> that will be passed to the
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.do-seek"><code class="function">GstBaseSrcClass.do_seek()</code></a> vmethod for executing a seek
request. Sub-classes should override this if they support seeking in
formats other than the configured native format. By default, it tries to
convert the seek arguments to the configured native format and prepare a
segment in that format.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.do-seek"></a>do_seek</code></em> ()</p></td>
<td class="struct_member_description"><p>Perform seeking on the resource to the indicated segment.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.unlock"></a>unlock</code></em> ()</p></td>
<td class="struct_member_description"><p>Unlock any pending access to the resource. Subclasses should unblock
any blocked function ASAP. In particular, any <code class="function">create()</code> function in
progress should be unblocked and should return GST_FLOW_FLUSHING. Any
future <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> function call should also return
GST_FLOW_FLUSHING until the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.unlock-stop"><code class="function">GstBaseSrcClass.unlock_stop()</code></a> function has
been called.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.unlock-stop"></a>unlock_stop</code></em> ()</p></td>
<td class="struct_member_description"><p>Clear the previous unlock request. Subclasses should clear any
state they set during <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.unlock"><code class="function">GstBaseSrcClass.unlock()</code></a>, such as clearing command
queues.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.query"></a>query</code></em> ()</p></td>
<td class="struct_member_description"><p>Handle a requested query.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.event"></a>event</code></em> ()</p></td>
<td class="struct_member_description"><p>Override this to implement custom event handling.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.create"></a>create</code></em> ()</p></td>
<td class="struct_member_description"><p>Ask the subclass to create a buffer with offset and size.  When the
subclass returns GST_FLOW_OK, it MUST return a buffer of the requested size
unless fewer bytes are available because an EOS condition is near. No
buffer should be returned when the return value is different from
GST_FLOW_OK. A return value of GST_FLOW_EOS signifies that the end of
stream is reached. The default implementation will call
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.alloc"><code class="function">GstBaseSrcClass.alloc()</code></a> and then call <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.fill"><code class="function">GstBaseSrcClass.fill()</code></a>.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.alloc"></a>alloc</code></em> ()</p></td>
<td class="struct_member_description"><p>Ask the subclass to allocate a buffer with for offset and size. The
default implementation will create a new buffer from the negotiated allocator.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstBaseSrcClass.fill"></a>fill</code></em> ()</p></td>
<td class="struct_member_description"><p>Ask the subclass to fill the buffer with data for offset and size. The
passed buffer is guaranteed to hold the requested amount of bytes.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrcFlags"></a><h3>enum GstBaseSrcFlags</h3>
<p>The <a href="../html/GstElement.html#GstElement-struct"><span class="type">GstElement</span></a> flags that a basesrc element may have.</p>
<div class="refsect3">
<a name="GstBaseSrcFlags.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="enum_members_name">
<col class="enum_members_description">
<col width="200px" class="enum_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="enum_member_name"><p><a name="GST-BASE-SRC-FLAG-STARTING:CAPS"></a>GST_BASE_SRC_FLAG_STARTING</p></td>
<td class="enum_member_description">
<p>has source is starting</p>
</td>
<td class="enum_member_annotations"> </td>
</tr>
<tr>
<td class="enum_member_name"><p><a name="GST-BASE-SRC-FLAG-STARTED:CAPS"></a>GST_BASE_SRC_FLAG_STARTED</p></td>
<td class="enum_member_description">
<p>has source been started</p>
</td>
<td class="enum_member_annotations"> </td>
</tr>
<tr>
<td class="enum_member_name"><p><a name="GST-BASE-SRC-FLAG-LAST:CAPS"></a>GST_BASE_SRC_FLAG_LAST</p></td>
<td class="enum_member_description">
<p>offset to define more flags</p>
</td>
<td class="enum_member_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstBaseSrc--blocksize"></a><h3>The <code class="literal">“blocksize”</code> property</h3>
<pre class="programlisting">  “blocksize”                <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a></pre>
<p>Size in bytes to read per buffer (-1 = default).</p>
<p>Flags: Read / Write</p>
<p>Default value: 4096</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrc--do-timestamp"></a><h3>The <code class="literal">“do-timestamp”</code> property</h3>
<pre class="programlisting">  “do-timestamp”             <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Apply current stream time to buffers.</p>
<p>Flags: Read / Write</p>
<p>Default value: FALSE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrc--num-buffers"></a><h3>The <code class="literal">“num-buffers”</code> property</h3>
<pre class="programlisting">  “num-buffers”              <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a></pre>
<p>Number of buffers to output before sending EOS (-1 = unlimited).</p>
<p>Flags: Read / Write</p>
<p>Allowed values: &gt;= -1</p>
<p>Default value: -1</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrc--typefind"></a><h3>The <code class="literal">“typefind”</code> property</h3>
<pre class="programlisting">  “typefind”                 <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Run typefind before negotiating (deprecated, non-functional).</p>
<p>Flags: Read / Write</p>
<p>Default value: FALSE</p>
</div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.see-also"></a><h2>See Also</h2>
<p><a class="link" href="GstPushSrc.html" title="GstPushSrc"><span class="type">GstPushSrc</span></a>, <a class="link" href="GstBaseTransform.html" title="GstBaseTransform"><span class="type">GstBaseTransform</span></a>, <a class="link" href="GstBaseSink.html" title="GstBaseSink"><span class="type">GstBaseSink</span></a></p>
</div>
</div>
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